Cell Signaling Technology

Product Pathways - siRNA

SignalSilence® Chk2 siRNA I #6276

Applications Reactivity
Transfection H

Reactivity Key:  H=Human
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa cells, transfected with 100 nM SignalSilence® Control siRNA (Unconjugated) #6568 (-) or SignalSilence® Chk2 siRNA I (+), using Chk2 (1C12) Mouse mAb #3440 and α-Tubulin (11H10) Rabbit mAb #2125. The Chk2 (1C12) Mouse mAb confirms silencing of Chk2 expression, while the α-Tubulin (11H10) Rabbit mAb is used as a loading control.

Description

SignalSilence® Chk2 siRNA I from Cell Signaling Technology (CST) allows the researcher to specifically inhibit Chk2 expression using RNA interference, a method whereby gene expression can be selectively silenced through the delivery of double stranded RNA molecules into the cell. All SignalSilence® siRNA products from CST are rigorously tested in-house and have been shown to reduce target protein expression by western analysis.

Quality Control

Oligonucleotide synthesis is monitored base by base through trityl analysis to ensure appropriate coupling efficiency. The oligo is subsequently purified by affinity-solid phase extraction. The annealed RNA duplex is further analyzed by mass spectrometry to verify the exact composition of the duplex. Each lot is compared to the previous lot by mass spectrometry to ensure maximum lot-to-lot consistency.

Directions for Use

CST recommends transfection with 100 nM Chk2 siRNA I 48 to 72 hours prior to cell lysis. For transfection procedure, follow protocol provided by the transfection reagent manufacturer. Please feel free to contact CST with any questions on use.

Each vial contains the equivalent of 100 transfections, which corresponds to a final siRNA concentration of 100 nM per transfection in a 24-well plate with a total volume of 300 μl per well.

Background

Chk2 is the mammalian orthologue of the budding yeast Rad53 and fission yeast Cds1 checkpoint kinases (1-3). The amino-terminal domain of Chk2 contains a series of seven serine or threonine residues (Ser19, Thr26, Ser28, Ser33, Ser35, Ser50, and Thr68) each followed by glutamine (SQ or TQ motif). These are known to be preferred sites for phosphorylation by ATM/ATR kinases (4,5). After DNA damage by ionizing radiation (IR), UV irradiation, or hydroxyurea treatment, Thr68 and other sites in this region become phosphorylated by ATM/ATR (5-7). The SQ/TQ cluster domain, therefore, seems to have a regulatory function. Phosphorylation at Thr68 is a prerequisite for the subsequent activation step, which is attributable to autophosphorylation of Chk2 at residues Thr383 and Thr387 in the activation loop of the kinase domain (8).

  1. Allen, J.B. et al. (1994) Genes Dev. 8, 2401-2415.
  2. Weinert, T.A. et al. (1994) Genes Dev. 8, 652-665.
  3. Murakami, H. and Okayama, H. (1995) Nature 374, 817-819.
  4. Kastan, M.B. and Lim, D.S. (2000) Nat. Rev. Mol. Cell Biol. 1, 179-186.
  5. Matsuoka, S. et al. (2000) Proc. Natl. Acad. Sci. USA 97, 10389-10394.
  6. Melchionna, R. et al. (2000) Nat. Cell Biol. 2, 762-765.
  7. Ahn, J.Y. et al. (2000) Cancer Res. 60, 5934-5936.
  8. Lee, C.H. and Chung, J.H. (2001) J. Biol. Chem. 276, 30537-30541.

Application References

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Companion Products

Limited Use Label License, RNA interference: This product is licensed under European Patent 1144623 and foreign equivalents from Ribopharma AG, Kulmbach, Germany and is provided only for use in non-commercial research specifically excluding use (a) in drug discovery or drug development, including target identification or target validation, by or on behalf of a commercial entity, (b) for contract research or commercial screening services, (c) for the production or manufacture of siRNA-related products for sale, or (d) for the generation of commercial databases for sale to Third Parties. Information about licenses for these and other commercial uses is available from Ribopharma AG, Fritz-Hornschuch-Str. 9, D-95326 Kulmbach, Germany.

For Research Use Only. Not For Use In Diagnostic Procedures.

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